FIG. 1 is a perspective view illustrating a conventional rack for communication equipment.
As shown in the drawing, a conventions rack 1 for communication equipment includes a rectangular base plate 2 and posts 4 that are mounted vertically on the base plate 2. Reinforcing plates 6 are attached to the posts 4 and bus bars 8 are fixed to the reinforcing plates 6.
A plurality of through-holes 10 is provided at the reinforcing plates 6 in a vertical line. Two groups of through-holes 10 provided at the respective reinforcing plates 6 are opposed to each other. Further, a plurality of cabling bars 12 is mounted to the reinforcing plates 6 in such a manner that both end portions of each cabling bar 12 are fitted through the two opposite through-holes 10.
A plurality of shelf units for storing communication equipment are mounted in the rack 1, which will be described with reference to FIGS. 2 and 3. A shelf unit 20 comprises a pair of side panels 22 and 24. It further comprises supporting plates 26 and 28 that are mounted to the top of the front and rear end portions of the side panels 22 and 24 for supporting them.
Front PCBs (printed circuit board) 40, which include a power unit and a PBA (printed board assembly) unit, are mounted in the front-half portion of the shelf unit 20. A back board 30, to which the front PCBs 40 are connected, is mounted in the central portion of the shelf unit 20. Rear PCBs 50 are mounted in the rear-half portion of the shelf unit 20 and connected to the back board 30. In order to support the front and rear PCBs 40 and 50, PCB guides 32 and 34 are mounted at the bottom of the front and rear end portions of the side panels 22 and 24. All components described above are coupled to one another by means of screws 36 and 38.
A procedure of demounting the back board 30 from the conventional shelf unit 20 is explained as follows. First, the front PCBs 40 and rear PCBs 50 are removed from the back board 30. Secondly, the screws 38 for fixing the supporting plate 28 and PCB guide 34 to the side panels 22 and 24 are released to separate the supporting plate 28 and PCB guide 34 from the side panels 22 and 24. Finally, the screws 36 for fixing the back board 30 to the shelf unit 20 are released to separate the back board 30 from the shelf unit 20.
Remounting the back board 30, supporting plate 28 and PCB guide 34 to the shelf unit 20 can be achieved according to the order that is reverse to the above-mentioned demounting procedure.
However, when demounting and remounting the back board from and to the shelf unit for repairs or maintenances, there is a problem in that a worker must also demount and remount other elements (e.g., the supporting plate, the PCB guide, etc.) by releasing and fastening a plurality of screws by hand. Therefore, it takes much time and labor to repair or replace the back board.
Further, it is very troublesome for the worker to align the screw holes of two corresponding elements when screwing them together.